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authorClaudius Heine <ch@denx.de>2022-05-10 09:48:51 +0200
committerRichard Purdie <richard.purdie@linuxfoundation.org>2022-05-11 17:16:11 +0100
commitce65ac2dd1d78ff0498e7ad84be833df81935380 (patch)
treeca24d037796a17166483de65b2cf79c267b6d027
parentdeb81cbb33e81cea8486d4bd86bc73f7b4b5d91d (diff)
downloadpoky-ce65ac2dd1d78ff0498e7ad84be833df81935380.tar.gz
overlayfs: add docs about skipping QA check & service dependencies
Add some documentation about skipping the QA check related to missing fstab entries or mount units for base mount points where the overlayfs is mounted from. Also add a short paragraph about adding a systemd unit dependency to services in recipes, so that they are started only after the overlayfs is mounted and ready. No functional change. (From OE-Core rev: 7adc49fa6fdbdf118f74e95193e80ae7ef019e27) Signed-off-by: Claudius Heine <ch@denx.de> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
-rw-r--r--meta/classes/overlayfs.bbclass18
1 files changed, 15 insertions, 3 deletions
diff --git a/meta/classes/overlayfs.bbclass b/meta/classes/overlayfs.bbclass
index 29fced2ca7..f7069edd41 100644
--- a/meta/classes/overlayfs.bbclass
+++ b/meta/classes/overlayfs.bbclass
@@ -16,10 +16,18 @@
16# 16#
17# OVERLAYFS_MOUNT_POINT[data] ?= "/data" 17# OVERLAYFS_MOUNT_POINT[data] ?= "/data"
18# 18#
19# The class assumes you have a data.mount systemd unit defined in your 19# Per default the class assumes you have a corresponding fstab entry or systemd
20# systemd-machine-units recipe and installed to the image. 20# mount unit (data.mount in this case) for this mount point installed on the
21# image, for instance via a wks script or the systemd-machine-units recipe.
21# 22#
22# Then you can specify writable directories on a recipe base 23# If the mount point is handled somewhere else, e.g. custom boot or preinit
24# scripts or in a initramfs, then this QA check can be skipped by adding
25# mount-configured to the related OVERLAYFS_QA_SKIP flag:
26#
27# OVERLAYFS_QA_SKIP[data] = "mount-configured"
28#
29# To use the overlayfs, you just have to specify writable directories inside
30# their recipe:
23# 31#
24# OVERLAYFS_WRITABLE_PATHS[data] = "/usr/share/my-custom-application" 32# OVERLAYFS_WRITABLE_PATHS[data] = "/usr/share/my-custom-application"
25# 33#
@@ -30,6 +38,10 @@
30# OVERLAYFS_MOUNT_POINT[mnt-overlay] = "/mnt/overlay" 38# OVERLAYFS_MOUNT_POINT[mnt-overlay] = "/mnt/overlay"
31# OVERLAYFS_WRITABLE_PATHS[mnt-overlay] = "/usr/share/another-application" 39# OVERLAYFS_WRITABLE_PATHS[mnt-overlay] = "/usr/share/another-application"
32# 40#
41# If your recipe deploys a systemd service, then it should require and be
42# started after the ${PN}-overlays.service to make sure that all overlays are
43# mounted beforehand.
44#
33# Note: the class does not support /etc directory itself, because systemd depends on it 45# Note: the class does not support /etc directory itself, because systemd depends on it
34# For /etc directory use overlayfs-etc class 46# For /etc directory use overlayfs-etc class
35 47